Effects of whey protein treatment in an <i>in vitro</i> intestinal cell model following oxidative stress or inflammatory challenge

Bovine milk whey proteins with an isoelectric point &gt;6.8 (‘whey’) have demonstrated anti-inflammatory and antioxidant properties. In the present study, pre-treatment of human intestinal cells (Caco-2) with whey mitigated intracellular reactive oxygen species produced in response to the pro-oxidant 2,2′-azobis (2-methylpropionamide)-dihydrochloride (AAPH). The mitigating effect was dose-dependent, and persisted when whey was removed prior to the addition of AAPH. Whey treatment also improved transepithelial electrical resistance (TEER), but returned to untreated-control levels upon removal of whey. Hence, whey can lead to cellular adaptations that aid intestinal function, but can exert additional properties while in contact with cells. Confocal imaging indicated that the previously observed TEER improvements in inflammatory-challenged Caco-2 monolayers were not due to the localisation of occludin or zonula occludens-1 tight junction proteins. However, proteomics analysis indicated a role for other tight junction proteins and provided insights into cellular adaptations that occur in response to whey pre-treatment.